Improvement in processes of developing photographic pictures



UNITED STATES PATENT OFFICE,

HENRY BUNDLE, OF EDWARDSVILLE, ILLINOIS, ASSIGNOR OF ONE-HALF HIS RIGHT TO GEORGE L. WILLIAMS, OF SAME PLACE.

IMPROVEMENT IN PROCESSES 0F DEVELOPING PHOTOGRAPHIC PICTURES.

Specification forming part of Letters Patent No. 204,760, dated June 11, 1878 application filed September 24, 1877.

off, and (preferably with cyanide of pot-as-' sinm) washed again in the ordinary manner. Then, without drying the plate, I pour over its surface an aqueous solution of sulphate of iron, alum, acetic acid, and corrosive sublimate, and compounded, preferably, in the following proportions: Of water, eight ounces; of sulphate of iron, two drams of alum, two drams; of acetic acid, one ounce; of corrosive sublimate, one-half ounce. The plate is subjected to the influence of this last-named or redeveloping solution until what are termed the whites of the picture assume a white marble appearance. The picture is then washed, and dried over an alcohol-lamp, heating the picture more than is customary, and preferably for a period of fifteen minutes. The moisture will then have thoroughly disappeared, and the impression be rendered permanent.

The effect of this treatment is to develop a photographic picture to a remarkable degree,

doI wish to be confined to the proportions above named in compounding the redeveloping solution. The amount of acetic acid may be varied from one-half to one and a half ounce; from one and three-fourths to two and a half drams of sulphate of iron maybe used; from one to two and a half drams of alum may be used; from one-fourth to threefourths of an ounce of corrosive sublimate may be used; and all may be dissolved in from six to ten ounces of water.

I claim- 1. The herein-described method of intensifying or redeveloping photographic pictures by treating them with a solution composed of sulphate of iron, alum, acetic acid, and corrosive sublimate, substantially in the proportions named.

2. As a new manufacture, the herein-described albertype picture upon a ferro-plate.

HENRY BUNDLE. vWitnesses:

OHAs. D. MooDY, FREDK. LEAR. 

